URI

Date

2011

Abstract

Vibration assisted forming is one of the most recent and beneficial technique used to improve forming process. Effects of vibration on metal forming processes can be attributed to two causes. First, the volume effect links lowering of yield stress with the influence of vibration on the dislocation movement. Second, the surface effect explains lowering of the effective coefficient of friction by periodic reduction contact area. This work is related to vibration assisted forming process in viscoplastic domain. Impact of change in vibration waveform has been analyzed. For this purpose, two analytical models have been developed for two different types of vibration waveforms (sinusoidal and triangular). These models were developed on the basis of Slice method that is used to find out the required forming force for the process. Final relationships show that application of triangular waveform in forming process is more beneficial as compare to sinusoidal vibrations in terms of reduced forming force. Finite Element Method (FEM) based simulations were performed using Forge2008®and these confirmed the results of analytical models. The ratio of vibration speed to upper die speed is a critical factor in the reduction of the forming force.

This paper presents the modelling of a forging processes assisted by a piezoelectric actuator (PA), which is used to generate specific low frequency vibration waveforms. Experimental results show that such waveforms reduce ...

Use of vibration in the forming process has already shown numerous advantages in the improvement of mechanical and surface properties of workpiece such as good surface or less friction between die and workpiece. The aim ...

This paper presents the design of a mechatronic system integrating iezoelectric multi-actuators, which is used to generate low-frequency vibrations to assist the forging process. With the aim of controlling the complete ...

This article addresses the effects of vibrations on a viscoplastic workpiece applied during the forgingprocess. To achieve this goal, a phenomenological model based on the slice method combined with aNorton–Hoff viscoplastic ...

This paper deals with the modelling of a piezo- electric stack actuator used to generate specific low frequency vibration waveforms to assist forging processes. Experimental results show that such waveforms reduce the ...